Insulated multi-wire cables may be used to conduct electricity from remote sources to electrical loads such as lamps and machines. These cables often terminate at points within the housings for the loads and have their wires connected, via solder, wire nuts, pin connectors, or otherwise, to circuitry within the load housings. The connections between the wires of a cable and internal load circuitry are relatively fragile; if sufficient tension is placed on the insulated cable the wires may separate from the internal circuitry at the connecting points and open the electrical path from the source to the load. Such failures not only disable the electrical appliance or device but often expose conductors, which may be dangerous, particularly in wet or explosive environments. These problems are compounded by the stresses placed on cables connecting sources to portable devices as the devices are moved from one location to another. In recognition of these dangers, Underwriters Laboratories, Inc. "UL") recently adopted a stricter strain relief test for portable electric lighting units intended for use in hazardous locations (UL Standard 781, as amended July 5, 1989).
Various devices have been designed to lessen the strain placed on cords or cables connecting sources to electrical loads. One simple apparatus for relieving tension on connection points between a cable and circuitry internal to a load is a grommet (or bushing) placed at the entry point of the cable into the load housing. Once threaded through the grommet the cable's movement is restricted by the grommet's small diameter opening, thereby preventing the cable section within the housing from moving freely in response to external forces. Because the cable is merely friction fitted into the grommet, however, some stresses encountered in normal operating environments for portable loads (particularly those comprising forces substantially coincident with the longitudinal axis of the grommet) continue to cause substantial movement of the cable and corresponding breakage of the electrical contacts between cable wires and internal load circuitry.